Jraft controller 支持设置Observer节点吗

### Before Creating the Bug Report

- [x] I found a bug, not just asking a question, which should be created in [GitHub Discussions](https://github.com/apache/rocketmq/discussions).

- [x] I have searched the [GitHub Issues](https://github.com/apache/rocketmq/issues) and [GitHub Discussions](https://github.com/apache/rocketmq/discussions) of this repository and believe that this is not a duplicate.

- [x] I have confirmed that this bug belongs to the current repository, not other repositories of RocketMQ.

### Runtime platform environment

linux

### RocketMQ version

rockketmq 5.2.0版本

### JDK Version

java11

### Describe the Bug

看代码支持解析/learner字符地址
java.lang.IllegalArgumentException: Fail to parse peerId:xxxx:9888/learner
at org.apache.rocketmq.controller.impl.JRaftController.initPeerIdMap(JRaftController.java:121)
at org.apache.rocketmq.controller.impl.JRaftController.(JRaftController.java:108)
at org.apache.rocketmq.controller.ControllerManager.initialize(ControllerManager.java:110)
at org.apache.rocketmq.controller.ControllerStartup.start(ControllerStartup.java:134)
at org.apache.rocketmq.controller.ControllerStartup.main0(ControllerStartup.java:56)
at org.apache.rocketmq.controller.ControllerStartup.main(ControllerStartup.java:49)

### Steps to Reproduce

1

### What Did You Expect to See?

1

### What Did You See Instead?

1

### Additional Context

1

Start at org.apache.rocketmq.controller.impl.JRaftController.initPeerIdMap, where the reported IllegalArgumentException occurs while parsing the peer address ending in /learner. Trace initialization through ControllerManager.initialize and reproduce the failure with the RocketMQ 5.2.0 controller configuration. Done means an observer or learner peer address is handled without preventing controller startup, with coverage for the supported address format.

Written by the indexing model from the issue text.